Conventionally, selective calling receivers have used an analogue signal as the selective signal. However, the use of digital signals as the selective signal has many functional advantages. In this case, the selective calling receiver includes a sound circuit which generates an audible sound as a calling signal and a visual display circuit which displays the message visually.
Liquid crystals, light emitting diodes (LED) etc., may be used as the display element of the visual display circuit. Liquid crystals have the disadvantage that their useful life is only about a year whereupon they must be replaced. Hence, light emitting diodes are frequently used. However, when using light emitting diodes, it is necessary to provide a control circuit for energizing the diodes only when the message is to be read in order to avoid power dissipation and short battery life. This control circuit is different from the control circuit which resets the sound circuit so as to stop the calling sound. Accordingly, it is a defect of selective calling receivers that use an LED display that they have many operating sections and that the operation of the LED display is difficult.
The method of resetting the sound circuit with a timer in order to simplify the operation has the disadvantage that the calling sound continues to be generated after it has attracted the attention of the recipient. This is particularly objectionable if the person receiving the call is in a meeting.
Selective calling receivers have accordingly heretofore had functional disadvantages as well as manufacturing disadvantages by reason of the number of parts required for the receiver and the labor involved in assemblying the parts.